CUSTOMER SITED IND ANDBOOK - NYSERDA · CUSTOMER SITED WIND HANDBOOK . 1 INTRODUCTION . The Customer Sited Wind Handbook was developed for the New York State Energy Research & Development

NEW YORK STATE

ENERGY RESEARCH AND

DEVELOPMENT AUTHORITY

CUSTOMER SITED WIND HANDBOOK

FINAL REPORT 10-08 AUGUST 2010

The New York State Energy Research and Development Authority (NYSERDA) is a public benefit corporation created in 1975 by the New York State Legislature

NYSERDA derives its revenues from an annual assessment levied against sales by New Yorkrsquos electric and gas utilities from public benefit charges paid by New York rate payers from voluntary annual contributions by the New York Power Authority and the Long Island Power Authority and from limited corporate funds

NYSERDA works with businesses schools and municipalities to identify existing technologies and equipment to reduce their energy costs Its responsibilities include

bull Conducting a multifaceted energy and environmental research and development program to meet New York Statersquos diverse economic needs

bull The New York Energy $martSM program provides energy efficiency services including those directed at the low-income sector research and development and environmental protection activities

bull Making energy more affordable for residential and low-income households

bull Helping industries schools hospitals municipalities not-for-profits and the residential sector implement energy-efficiency measures NYSERDA research projects help the Statersquos businesses and municipalities with their energy and environmental problems

bull Providing objective credible and useful energy analysis and planning to guide decisions made by major energy stakeholders in the private and public sectors

bull Since 1990 NYSERDA has developed and brought into use successful innovative energy-efficient and environmentally beneficial products processes and services

bull Managing the Western New York Nuclear Service Center at West Valley including overseeing the Statersquos interests and share of costs at the West Valley Demonstration Project a federalState radioactive waste clean-up effort and managing wastes and maintaining facilities at the shut-down State-Licensed Disposal Area

bull Coordinating the Statersquos activities on energy emergencies and nuclear regulatory matters and monitoring low-level radioactive waste generation and management in the State

bull Financing energy-related projects reducing costs for ratepayers

For more information contact the Communications unit NYSERDA 17 Columbia Circle Albany New York 12203-6399 toll-free 1-866-NYSERDA locally (518) 862-1090 ext 3250 or on the web at wwwnyserdaorg

STATE OF NEW YORK ENERGY RESEARCH AND DEVELOPMENT AUTHORITY David A Paterson Governor Vincent A DeIorio Esq Chairman

Francis J Murray Jr President and Chief Executive Officer

2010 Customer Sited Wind Handbook

Prepared for New York State Energy Research and Development Authority 17 Columbia Circle Albany NY 12203

Prepared by AWS Truewind 463 New Karner Road Albany NY 12205

reowpd

cerouS

FOREWORD The Customer Sited Wind Handbook was developed under the New York

State Energy Research and Development Authority (NYSERDA) under the PON 995 Agreement 9998 NYSERDA is a public benefit corporation created in 1975 under Article 8 Title 9 of the State Public Authorities Law through the reconstitution of the New York State Atomic and Space Development Authority

This publication was written by AWS Truewind LLC The intent of this handbook is to contain background information and practical guidelines for typical on-site generation and small wind installations

The principal authors were Dan Ryan and James Doane of AWS Truewind LLC Contributing authors were Julien Bouget Daniel Bernadett Marie Schnitzer also of AWS Truewind LLC

NOTICE The opinions expressed in this report do not necessarily reflect those of NYSERDA or the State of New York and reference to any specific product service process or method does not constitute an implied or expressed recommendation or endorsement Further NYSERDA the State of New York and the contractor make no warranties or representations expressed or implied as to the fitness for particular purpose or merchantability of any product apparatus or service or the usefulness completeness or accuracy of any processes methods or other information contained described disclosed or referred to in this report NYSERDA the State of New York and the contractor make no representation that the use of any product apparatus process method or other information will not infringe privately owned rights and will assume no liability for any loss injury or damage resulting from or occurring in connection with the use of information contained described disclosed or referred to in this report

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TABLE OF CONTENTS

FOREWORD 2

TABLE OF FIGURES 5

1 INTRODUCTION 6

11 Small Wind Implementation Guidelines 7

2 IS WIND ENERGY RIGHT FOR ME 8

3 THE WIND RESOURCE 9

31 What is the Wind Resource 9 Available Power 9 Variability and Shear 9 Turbulence 10

32 Wind Resource Assessment 11 Collecting Wind Resource Data 11 Wind Resource Map 12 Wind Rose 13 Frequency Distribution 14

4 WIND TURBINE TECHNOLOGY 15

41 What is Small Wind 15 42 Wind Energy Applications 16

Water Pumping 16 Battery Charging 16 Grid-Connected 16

43 Turbine Technology 18 Horizontal-Axis Wind Turbines (HAWT) 18 Vertical-Axis Wind Turbines (VAWT) 21 Performance Metrics 22

5 SITING ANALYSIS 24

51 Site Access 24 52 Performance 24

Obstructions 24 Collection System 26

53 Safety 26 54 Social 27

Aesthetics 27 Acoustics 28 Shadow Flicker 29

55 Zoning and Permitting 29

3 | P a g e

6 ENERGY PREDICTION 30

61 Small windExplorer 30 62 Methodology 32

Wind Shear Adjustment 33 Frequency Distribution 34 Power Curve 34 Air Density Adjustment 36 Losses 37 Uncertainty 38

63 Economic Analysis 38

7 NYSERDA INCENTIVE 39

8 OPERATIONS AND MAINTENANCE 40

81 Installation 40 82 Maintenance 40 83 Follow-Up Inspections 41

9 CASE STUDIES 42

91 Alfred University Alfred State College Farm 42 92 Apple Pond Farming Center 44 93 Olde Chautauqua Farm ndash Portland NY 46 94 Weimann Farm ndash Locke NY 48

10 APPENDIX 50

A1 Zoning and Permitting 50 Where to Start 50 Permits and Codes 51 State Environmental Quality Review Act 52

A3 Small windExplorer Instructions 56 How to Navigate the Application 56 How to Generate a Report 57 How to Interpret the Basic Report 58 How to Interpret the Advanced Report 59

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TABLE OF FIGURES Figure 1 Steps to successfully implement a small wind system 6

Figure 2 Relationship between turbine height and power output 10

Figure 3 Example of a wind resource map for New York State 12

Figure 4 Diagram of a typical wind rose 13

Figure 5 Frequency distribution of wind speed and energy 14

Figure 6 Size comparison of various wind turbines 15

Figure 7 Diagram of VAWT (L) and HAWT (R) turbine designs 18

Figure 8 Self-supporting lattice tower 20

Figure 9 Comparison of measured and binned averaged power curves 22

Figure 10 Approximate region of turbulent airflow 25

Figure 11 Turbine sound pressure levels 28

Figure 12 Methodology of the Small windExplorer 32

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1 INTRODUCTION The Customer Sited Wind Handbook was developed for the New York

State Energy Research amp Development Authority (NYSERDA) to help educate and guide end-users of small wind energy systems The documentrsquos intended audience includes those interested in purchasing a wind energy system and small wind installers located throughout New York State The handbook focuses on small-scale wind turbines but much of the content will serve as a useful introduction to wind energy in general and can be applied to wind projects of all sizes

For many small wind and community wind installations a detailed wind resource assessment and feasibility study may not be economically justified Therefore this handbook was created to help facilitate the future siting planning and development of these types of installations Overall this handbook is aimed at helping the end customer make informed decisions regarding the viability of wind generation at their site and will recommend steps and procedures that increase the likelihood of successful projects While the handbook focuses mostly on smaller wind systems it also provides insight on when resource assessment campaigns or detailed feasibility studies may be warranted on larger scale end-use installations

This handbook will present the basics of wind energy and the steps involved in determining the available wind resource at a specific site analyzing the proposed sitersquos surroundings and calculating the estimated annual energy production of the system This discussion will help home owners determine the wind energy potential of their property before contacting an eligible installer and will help installers conduct consistent and accurate site evaluations

The graphical flowchart in Figure 1 displays steps for a successfully implemented small wind system The flowchart also provides an overview for the chapters of the handbook

Figure 1 Steps to successfully implement a

small wind system

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11 Small Wind Implementation Guidelines

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2 IS WIND ENERGY RIGHT FOR ME While wind energy currently plays only a small role in the worldrsquos

energy supply its use is growing rapidly Along with the larger utility scale projects more and more home owners are taking advantage of the power in the wind by installing small wind turbines on their property

Before installing a small scale wind turbine at your home or business it is important to consider the energy consumption and efficiency of the property These options can significantly reduce your propertyrsquos energy requirements and will subsequently reduce the required size of the renewable energy system Additionally money spent increasing the efficiency of your home will typically result in a better energy payback than a renewable energy system

Renewable energy systems can help further reduce your electricity bill and could possibly feed electricity back into the grid They also offer attractive environmental alternatives to the electricity from the grid

Before purchasing and installing a renewable energy system determine if it is right for you and your property Depending on your location and surroundings different renewable energy technologies will produce different amounts of energy A small wind energy system may be economical and provide a resonable amount of energy if

bull you have reduced consumption and increased the energy efficiency of your property

bull your property has a sufficient wind resource

bull your property has an open field or is void of major obstacles

bull long term investments are acceptable

If you determine that wind energy is right for you and want to continue investigating your propertyrsquos wind energy potential the following chapters in the handbook will help guide you through the subsequent steps to successfully implement a small wind energy system

There are many options for decreasing your propertyrsquos energy consumption and increasing its efficiency Simple steps to decrease consumption include bull Turn off lights when not in

use and unplug rarely used appliances

bull Reduce the temperature of your water heater

bull Adjust your thermostat to a cooler setting in the winter and a warmer setting in the summer

Additional steps that can be taken to increase the long term efficiency of your property include the following bull Minimize air leakage by air

sealing your home bull Install compact fluorescent

light bulbs bull Increase the propertyrsquos

outer wall insulation using rigid foam or spray material

bull Install low-E argon gas casement windows

bull Purchase high efficiency appliances

Additional resources for improving the energy efficiency can be found at the NYSERDA Get Energy $mart Web site wwwgetenergysmartorg

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3 THE WIND RESOURCE Once you have decided to further pursue a wind energy system it is

important to understand the wind resource and know how it will affect your turbinersquos energy production This chapter will familiarize you with wind energy and the main tools used to quantify your propertyrsquos available wind resource

31 What is the Wind Resource

Wind turbines are designed to capture a portion of the windrsquos kinetic energy and convert it into mechanical energy to generate electricity The amount of energy that a turbine can harvest from the wind depends on a number of factors including turbine design wind speed and wind quality The term wind resource is a broad term that is used to describe the characteristics of a sitersquos available wind Potential installation sites are initially evaluated based on wind speed and direction data for the project location and hub height Since a sufficient wind resource is crucial for an efficient and economically viable turbine installation it is used to both site the turbine and predict system performance

Available Power

To evaluate potential sites and estimate the available wind resource the factors that influence the wind speed and subsequently the power in the wind must be understood To begin the effect that the wind speed has on the windrsquos available power will be discussed Air has mass and when in motion it possesses energy known as kinetic energy The amount of available power in the wind is dependent on a number of factors including air density wind speed and the swept area of the turbine blades

As is evident from the equation on the right an increase in the air density swept area or wind speed will increase the available power Still the available power in the wind is proportional to the cube of the wind speed For instance if the wind speed is doubled the available power in the wind is increased by a factor of eight This nonlinear dependence makes the wind speed the most important factor at the installation site

Variability and Shear

A sitersquos wind speed will vary greatly for a given project area due to many influencing factors including time of day season height terrain and land cover The speed changes over time can be difficult to estimate therefore the

copy Q

rsquos P

The power available in the wind is calculated using the following equation

Where p = Air density A = Swept area of blades V = Wind speed

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Turbulence intensity is calculated using the following equation

Where 0 = Standard deviation of wind speed V = Mean wind speed

wind resource is usually characterized by its average annual wind speed As a general rule and a requirement for NYSERDA sponsored incentives (wwwPowerNaturallyorg) the average annual wind speed at the turbine location and hub height must be at least 10mph this guideline is usually a good indicator of a potentially good wind resource

In addition to inter-annual variations the wind speed is related to the height above ground The speed of the wind decreases near the earthrsquos surface due to a frictional drag experienced between the wind and the surrounding environmentrsquos surface roughness caused by items like terrain ground cover and buildings The magnitude of this occurrence known as wind shear will vary with changes in the environment and surface roughness

The surrounding environmentrsquos effect on the wind decreases with increasing height above ground resulting in an increase of speed with increasing distance from the ground A slight increase of wind speed due to an increase in height will lead to a significant increase of wind power This relationship highlights the importance of having a sufficiently tall tower to place the turbine in high velocity winds Towers of 80 to over 120 feet are typically used in New York for this reason The graph in Figure 2 further illustrates the typical relationship between height and power production The

Figure 2 Relationship between turbine height and power output

relationship between height and power production at a particular site will be affected by the mean wind speed surface roughness and terrain

Turbulence

Small scale variations in the wind resource can be detrimental to the turbine These variations known as wind turbulence are described as rapid disturbances or irregularities in the wind speed direction and vertical component Turbulence will vary with height and location and is caused by many different factors including manmade structures vegetation and topography It is an important site characteristic since high turbulence levels may decrease power output and cause extreme loading on wind turbine components which will result in increased fatigue and possible failure The most common indicator of turbulence for siting purposes is the standard deviation (0) of wind speed Normalizing this value with the mean wind speed gives the turbulence intensity (TI) This value allows for an overall assessment of a sitersquos turbulence TI is a relative indicator of turbulence with low levels

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indicated by values less than or equal to 010 moderate levels to 025 and high levels greater than 0251

32 Wind Resource Assessment

In order to properly identify the wind energy potential of a site and determine the feasibility and economic viability of a small wind system the wind resource must be quantified to produce a reasonable energy production estimate for the turbine Specifically the annual average wind speed wind rose and wind speedrsquos probability distribution for the proposed turbine location and hub height are important parameters The following sections will describe the process of collecting this information and the tools used to display the characteristics of the wind resource

Collecting Wind Resource Data

Wind resource data is typically collected using meteorological towers with anemometers and wind vanes at multiple heights and a collection time of at least one year in order to properly describe local seasonal variations This type of measurement campaign is needed for utility scale wind energy projects and can be justified for community scale projects with a small number of utility scale turbines Nevertheless this type of campaign is rarely economically justified for small wind installations due to the high cost of equipment installation and monitoring Therefore a simpler and quicker method of characterizing the wind resource is necessary To help determine the wind

resource in New York State NYSERDA has developed an interactive online tool specifically created for small wind installations Small windExplorer This tool is discussed in detail in Chapter 6 along with the discussion of turbine energy production On-site resource assessment campaigns or feasibility studies may be warranted for end-use or community wind projects greater than 100 kW

Anemometer amp Wind Vane

(Photos courtesy of NRG Systems Inc)

Anemometers and wind vanes are meteorological instruments that are used to measure the available wind resource Anemometers are used measure the wind speed and wind vanes are used to measure the wind direction Examples of the two instruments are shown below

Small wind installations in New York State can take advantage of the Small windExplorer This is an important first step in determining if the property is suitable for wind energy A Basic Report can be created for the site which will help determine if there is enough wind on the property

The property owner should contact an eligible installer with the Basic Report information The installer will guide the end-user through the entire process of assessing the wind resource siting the turbine applying for the NYSERDA incentive installing the turbine and conducting regular maintenance on the system

1 httpwwwnrelgovwindpdfs22223pdf 11 | P a g e

Wind Resource Map

As mentioned earlier the annual average wind speed is one of the most important parameters used to describe a sitersquos wind energy potential This information can be displayed as a table of wind speeds for varying heights at the project location or in a graphical wind resource map for a specific height As shown in Figure 3 a typical wind resource map displays the average annual wind speed for varying locations at a defined height Wind maps are generated using observed historical data and numerical weather models they provide the user with an estimate of the wind resource without on-site measurement

High quality wind maps depict the approximate annual average wind speed over small (200m) grid cells at the indicated height above ground and allow the user to determine the locations with the best wind resource While this tool can be used in determining site specific wind data it must be made clear that the estimates are averaged over the grid cell For instance in determining the wind speed at a specific latitude and longitude the tool will choose the closest grid point to the chosen location and display the averaged wind data for the entire cell area This grid point is based on averaged site data for the grid cell and may not accurately depict small scale changes in wind speed and roughness throughout the cell Therefore a given wind speed for a grid cell may be higher or lower than the exact location being studied

Figure 3 Example of a wind resource map for New York State

In order to receive a reasonable return for your investment the hub height annual average wind speed must be greater than 10 miles per hour If the Small windExplorer estimates that property has an insufficient wind resource other renewable energy options should be explored

12 | P a g e

Wind Rose

Wind direction varies on both small and large time scales and all directions have different amounts of available energy An estimate of the amount of energy from each directional sector at the proposed installation site is needed to help quantify how local obstacles and the surrounding environment may influence the systemrsquos energy production

The typical method for characterizing and displaying the distribution of the wind speed is through the use of a wind rose A wind rose graphically displays the percent time and percent energy of the wind for the directional sectors and is usually divided into eight or sixteen sections The percent energy differs from the percent time because the energy in the wind is proportional to the cube of the wind speed as discussed earlier Therefore a certain direction that has a low wind speed for a long period of time may have less energy than a direction that has high wind speeds for a shorter amount of time

This graphical tool is extremely helpful in the siting of small wind systems it helps to determine the prevailing wind directions that will be impacted most by local obstacles The wind rose used in conjunction with the wind map and other siting criteria helps the land owner and installer determine the best possible location throughout the installation property to maximize the turbinersquos energy production

ewurTS

Figure 4 Diagram of a typical wind rose

As shown in the above wind rose the percent of total time is represented with gray wedges and the percent of total energy is represented with blue wedges The radius of each wedge gives the respective percentage for each directional sector as defined by the radial markings from the center

The wind rose has a prevailing wind direction from the southeast with approximately 29 of the total energy The south and northwest also have substantial wind energy totaling 22 and 21 respectively Trees or other obstacles in these directions could significantly reduce the output of a turbine

13 | P a g e

Figure 5 Frequency distribution of wind speed and energy

Frequency Distribution

Wind is an intermittent resource and varies in strength with time of day season and year If wind speed measurements were taken at a project site for an entire year and graphed the speed distribution would resemble a bell shape with a low probability of zero wind speeds and a low probability of very high wind speeds Additionally the wind speed is usually skewed with higher velocity winds occurring less often than the lower speeds as shown in Figure 5

Since the energy in the wind is proportional to the cube of the wind speed the amount of energy in the wind at higher velocities is much higher than that at lower velocities Therefore two sites with the same annual average wind speed may have different wind energy potentials due to different wind speed distributions For this reason it is very important to understand the frequency distribution of the wind speeds to accurately estimate the amount of power available at the site

Since it is not economically feasible to conduct a long-term measurement campaign to determine the speed distribution for small wind projects the wind speed frequency distribution is usually modeled using mathematical functions Wind speeds are typically divided into 1ms increments or bins and described using a Weibull distribution This distribution is calculated using a shape factor (k) a scale factor (A) and the average annual wind speed Furthermore the distribution will change from site to site and for different hub heights so the parameters are needed at the turbinersquos specific location and hub height

The Small windExplorer automatically inserts the site specific Weibull parameters to calculate the windrsquos frequency distribution Additionally the Small windExplorer advanced report provides the shape (k) and scale (A)factors for advanced users to use in other energy estimating tools

The Weibull distribution is described using the following equation

Where p(U) = Probability wind speed will be between U and U+1 (in ms) k = Weibull scale factor A = Weibull shape factor

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4 WIND TURBINE TECHNOLOGY Once the wind resource is identified and the decision to move forward

with a wind energy project is made it is important to understand turbine technology and the many components of a small wind system This chapter will give land owners and installers a deeper understanding of the various types of turbines and will help home owners learn more about the technology before investing in a system

Figure 6 Size comparison of various wind turbines

Utility-scale Medium-scale Rated Power 15 MW Rated Power 250 kW

Hub Height 80 m Hub Height 42 m Rotor Diameter 77 m Rotor Diameter 30 m

Small-scale Rated Power 10 kW

Hub Height 30 m Rotor Diameter 7 m

41 What is Small Wind

Wind turbines are generally categorized based upon their nominal power which is the power output at a rated wind speed Based upon the nominal power output turbines can be classified into one of three categories small medium and utility scale Small-scale wind turbines typically include units with a nominal power output under 100 kW and are predominantly used by homeowners and businesses to offset local energy consumption Medium-scale turbines typically include those with a nominal power between 100 kW and 1000 kW and are used by larger businesses or small wind farms Utility-scale wind turbines with a typical nominal power greater than 1000 kW are used in large wind farms where the electricity is sold to an energy utility While these categories are by no means concrete they serve a helpful classification when referencing turbines of similar production capacity and technology Figure 6 below gives a relative size comparison for small medium and large turbines

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The consumption of the property must be analyzed to help choose the correct size turbine and ensure optimum electrical production Electrical demands can require a turbine of as small as a few kilowatts for a small house to several dozen kW for a small commercial property The propertyrsquos annual consumption should be compared to the estimated production of the turbine

42 Wind Energy Applications

Wind energy is currently used in many different areas and for many different applications Wind can be captured to pump water for livestock or irrigation or can be used to generate electricity Each different application requires different components and equipment

Water Pumping

Water pumping is often required in remote locations for drinking water for personnel or livestock Since water is easily stored the intermittent nature of the wind is easily mitigated by pumping water when the wind is available and storing it for times when the wind is not blowing Wind turbines can either drive water pumps directly via a shaft or produce electric power which in turn is used by an electric water pump Since electric water pumps are able to directly use the variable frequency AC generated by a wind turbine with a permanent magnet generator no inverter or battery bank is required Wind power can be used to pump other liquids such as petroleum but water pumping is far more common

Battery Charging

The power generated by a wind turbine is often stored in a battery bank for use at a later time Deep-cycle batteries are best for this type of application because they can charge and discharge 80 of their capacity hundreds of times A charge controller is needed to prevent battery damage as a result of overcharging the controller will protect the batteries by either dumping or diverting excess electricity

As discussed earlier many small wind turbines have permanent magnet generators that output variable frequency AC which is subsequently converted to DC Batteries store DC energy and for small end-use applications DC-compatible appliances can be operated directly from the battery bank In order to use the electricity generated by the turbine in a household a power-conditioning unit known as an inverter is generally used to convert the DC electricity into 60 Hz 120 V AC

Grid-Connected

When the electrical grid is easily accessible the turbine is usually connected to the grid This configuration allows the end-user to use electricity from the grid when the turbine is not producing sufficient power and eliminates the userrsquos need for a battery bank An inverter is required to connect a

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Additional information on New York Statersquos net-metering and interconnection requirements can be found at the NYS distributed generation Web site (wwwdpsstatenyusdistgenhtm) and the NYSERDA Web site (wwwnyserdaorg)

permanent magnet generator to the electric grid No inverter is required to connect an induction generator to the grid

Through a program called net metering excess electricity is sold to the utility at the same price that the utility charges the turbine owner for utility-supplied electricity Under this type of arrangement producers of renewable energy receive credits for every kWh they generate beyond their own needs When a turbine owner produces more electricity than can be used locally the power meter runs backwards sending the excess electricity to the grid New York State currently has system size limitations for net metering with wind energy 25 kW for residential systems 500 kW for farm-based systems and 2 MW or peak load for non-residential systems If more than 100 of consumption is produced by the system the excess energy is paid back at the avoided cost of production by the closest production source Since the avoided cost of production is usually a fraction of the retail electricity rate it does not make financial sense to over-size a turbine with the intent of making money on excess electricity that is sold back to the utility

While all three applications play an important role in the generation of usable energy from the wind the water pumping and battery sections are only provided for context The following sections of the handbook will refer only to grid connected systems

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Figure 7 Diagram of VAWT (L) and HAWT (R) turbine designs

For a list of turbines participating in NYSERDArsquos incentive program see wwwPowerNaturallyorg

43 Turbine Technology

There are two basic wind turbine designs the horizontal-axis wind turbine (HAWT) and the vertical-axis wind turbine (VAWT) As the names imply the HAWT features a rotor that is mounted horizontally with a rotational axis parallel to the ground while the VAWT has a rotor that rotates about an axis perpendicular to the ground Since VAWTs rotate about a vertic al axis they are always oriented into the wind HAWTs can be subdivided further based upon the turbinersquos orientation to the wind Upwind turbines are oriented into the direction from which the wind is blowing while downwind turbines face away from the direction of the wind Figure 8 below shows the two basic types of wind turbine designs

Horizontal-Axis Wind Turbines (HAWT)

Horizontal-axis small-scale wind turbines are the most prevalent design and usually consist of the following components

bull Rotor to convert wind energy to the rotating shaft

bull Generator to convert the rotational energy to electricity

bull Yawing mechanism to control turbine orientation

bull Tower to support the above components

bull Control system for high wind events

The rotor captures the kinetic energy of the wind and converts it into torque which is then transmitted through a rotational shaft to the generator The rotor usually consists of two or three blades that are connected to a hub and central shaft that drives the generator The blades are typically constructed out of composite material such as fiberglass due to its strength and flexibility and range in length from 25-50 feet The complexity of the rotor system can vary greatly based upon the size and sophistication of a turbinersquos design

The blades of most small-scale wind turbines have a simple fixed pitch system where the bladersquos pitch angle is constant Larger utility-scale variable speed turbines have a more advanced pitch system that adjusts the blade angle to control the rotation of the rotor in varying wind conditions

18 | P a g e

19 | P a g e

Generator

The generator converts the rotational energy of the shaft into electricity using electromagnetism There are two different types of generators used in small wind turbines permanent magnet and induction Many small wind turbines up to 50 kW use permanent magnet generators In this type of system the rotor is connected directly to the rotational shaft of a permanent magnet alternator which produces alternating current However the frequency of the alternating current is proportional to the rotational speed of the blades Since this variable frequency AC power is incompatible with standard 60 Hz AC systems it is typically converted to DC power This DC power can then be used directly by DC devices stored in batteries or converted to 60 Hz AC power

Most turbines above 50 kW use induction generators Induction generators require grid power to magnetize the generator and produce 60Hz AC that is compatible with the electrical grid Therefore induction generators do not require an inverter for power conditioning

Additionally many small wind turbines use a direct drive system meaning that the rotational shaft is connected directly to the generator Larger wind turbine designs often use a gearbox to increase the rotational speed of the slowly rotating main shaft

These components are usually housed at the top of the turbinersquos tower in an enclosure known as the nacelle

Yawing Mechanism

Yaw refers to the rotation of the turbine about its vertical axis and is used to align the turbine with the wind Most medium- and utility-scale turbines have active yawing mechanisms where a control system linked to a wind vane determines the wind direction When the control system detects a change in wind direction yaw motors are activated to turn the rotor into the wind to maximize energy capture

The majority of small-scale turbines use a passive yaw system which uses the wind rather than motors to orient the position of the turbine Passive yaw systems for upwind designs consist of a tail or vane that extends out from the rear of the turbine The turbinersquos tail operates similar to a weather vane it orients the rotor to face into the direction of the wind Turbines with a downwind design also yaw passively and self-align with the wind without the use of a tail

Advantages bull HAWTs are usually mounted on tall

towers exposing them to stronger winds which greatly improves the potential for energy production and reduces the harmful effects of ground-induced turbulence

Disadvantages bull The major components of small-scale

HAWTs are located at the top of the tower making them difficult to access without the use of a tilt-down tower

bull HAWTs require a yawing mechanism to orient the rotor into the direction of the wind thereby creating a risk of yaw misalignment

Upwind vs Downwind Unlike upwind oriented turbines downwind turbines do not require a yawing mechanism because they are designed to self-align with the direction of the wind Downwind turbines are subjected to increased fatigue loading due to the distorted flow behind the tower

Figure 8 Self-supporting lattice tower

Figure 8 Self supporting lattice tower

Small wind turbines can be mounted on tall towers (80 ft or higher) and are either self-supporting or guyed The towers are composed of smaller sections of triangular lattice pipe or tubing and are typically constructed on-site Self-supporting towers rely on a strong steel frame and concrete foundation to keep them upright while guyed towers are supported by tensioned cables and anchors positioned around the base of the tower for stability

Guyed towers are usually less expensive and easier to install than self-supporting towers Additionally some guyed towers have a hinge at their bases allowing them to be tilted up or down using a gin pole and a winch for maintenance and repairs Due to the guyed towerrsquos large footprint it may not be suitable for certain situations the radius of the guy foundation needs to be one-half to three-quarters the height of the tower while a freestanding tower only occupies the area of the tower foundation

The tower itself can consist of lattice section pipe or tubing Lattice towers are typically constructed out of triangular lattice sections that bolt together this type of tower can be self-supporting or guyed depending upon the design of the structure A tower can be assembled from several sections of metal tubing that fit together end-to-end Tubular towers can be either self-supporting or guyed

Control System

In larger utility-scale turbines the blades are able to rotate about their axes altering the angle at which the blade intercepts the wind This system known as pitch control is used to optimize power output at low wind speeds and regulate operation during high wind speeds which prevents overspeeding by shedding excess energy Small wind turbines generally donrsquot have pitch control so they use different methods to shed excess energy and protect themselves in high winds Small wind turbines deal with excessively high wind in one or more of these three ways they stall turn out of the wind or deploy tip brakes With a passive stall control system the turbine blades are designed to generate turbulence on the upwind side of the blade above a given wind speed This turbulence causes the turbine blades to stall instead of producing lift so the rotation of the blades is slowed

20 | P a g e

Another passive control system allows the turbine to turn out of the wind either horizontally or vertically Turning horizontally out of the wind is referred to as yaw Turning vertically out of the wind is referred to as tilt

Tip brakes employ weights that are placed on the tips of the turbine blades When the rotational speed of the blades exceeds a certain threshold the weights flare outwards due to the centrifugal force When this happens the shape of the tip brakes causes aerodynamic drag which in turn slows the rotor

Vertical-Axis Wind Turbines (VAWT)

Vertical axis wind turbines rotate about an axis perpendicular to the ground and are usually one of three designs Darrieus Giromill and Savonius Large-scale VAWTs usually take the form of a Darrieus design often likened to an ldquoeggbeaterrdquo because their long C-shaped blades bow out from the turbinersquos vertical axis This type of turbine is usually ground-mounted and the central tower is held upright by guyed wires This VAWT design is not self-starting and usually requires an external power source to initiate rotation

A more common design for small-scale VAWTs is referred to as a Giromill or H-bar model Instead of the long curved blades of the Darrieus design the Giromill uses straight vertical blade sections which are attached to the vertical axis with horizontal supports

The third type of VAWT Savonius is based on drag and uses ldquoscoopsrdquo to catch the wind The Savonius is able to start by itself unlike the Darrieus or Giromill which must be started by an external source such as a motor

Vertical axis turbines will typically have many of the same components as the horizontal axis turbine rotor gearbox and generator Nevertheless since they perform independently of the wind direction they do not need a yawing mechanism or control system VAWTs can be located near the ground or on a tower For more information on the system components please refer to the above section

Advantages bull The design is always aligned with the

wind so there is no need for a yaw mechanism

bull Several of the turbinersquos major components including the gearbox and the generator are ground-mounted making them easily accessible for maintenance

bull VAWTs are often installed lower to the ground than HAWTs so they can be installed in areas with height restrictions

Disadvantages bull Since VAWTs are located near the

ground they are exposed to lower wind speeds and higher turbulence

bull Some VAWT designs are not self-starting and need an initial boost to rotation

bull The weight of the turbine is supported by the ground-mounted components this means that major repairs or the replacement of parts can require that the system be completely dismantled

bull VAWTs can be more difficult to control in high winds because they cannot be turned out of the wind

Darrieus Giromill Savonius

21 | P a g e

Performance Metrics

Power Curve

Small wind turbine performance can be described using a manufacturer supplied power curve which shows the turbinersquos output power versus hub height wind speed standardized to sea level air density (1225 kgm3) The wind speeds are listed on the horizontal axis in miles per hour (mph) or meters per second (ms) and the turbinersquos power output is along the vertical axis in either watts or kilowatts (kW)

The power curves above have certain points that provide specific information regarding the turbines performance The cut-in speed at the lower end of the curve is the threshold that the hub height wind speed must reach in order for the turbine to begin generating electricity A turbinersquos nominal or ldquoratedrdquo power is the amount of electricity that the turbine will generate at a manufacturer specified wind speed this value is often used to describe a turbinersquos generating capacity The rated power is often confused with the turbinersquos peak power located at the very top of the curve which indicates the maximum amount of power the turbine can produce The turbinersquos governing speed is the wind speed at which the turbine will protect itself from high wind speeds since small wind turbines are subjected to large structural loads at high wind speeds

Using either the rated power or the peak power as a basis of comparison between turbines can be misleading for two reasons Wind turbine manufacturers donrsquot all rate their turbines using the same wind speed and the turbines are exposed to the wind speeds associated with rated or peak power only a small percentage of the time It is more useful to compare turbine performance at the lower end of the curve considering that the turbine will be operating at those wind speeds the majority of the time Upcoming AWEA standards for small wind turbines will improve the ability to compare turbines by defining AWEA rated power at and 11 ms wind speed and AWEA rated energy as the expected annual energy from a turbine at a location with an annual average wind speed of 5 ms (112 mph)

A power curve is usually assembled from ten-minute averages of a turbinersquos power production at a given wind speed A plot of a turbinersquos actual power production is much more scattered than the simple power curve that is provided by manufacturers The plots in Figure 9 below compare observed power data with a power curve constructed from the average power production for each wind speed bin or increment

Measured Power Data

Bin Averaged Power Data

Figure 9 Comparison of measured and binned averaged power curves

22 | P a g e

The capacity factor is calculated using the equation below

To calculate the CF for a given year divide the expected or actual annual production by the rated capacity multiplied by the number of hours in the year as shown below

Capacity Factor

To measure the productivity of a wind turbine wind farm operators use a metric known as capacity factor This variable compares the wind plantrsquos actual production to its theoretical production that would result from the plant running at nominal capacity over a given amount of time To calculate the capacity factor the annual energy production is divided by the rated power multiplied by the number of hours in the year This performance metric normalizes the data and allows easy comparison between different turbine technologies sizes and locations

Most utility-scale wind farms operate between 65 and 90 of the time and are often not operating at their rated capacity Therefore a capacity factor of 25 to 40 is typical for these utility scale systems Given that small-scale turbines use much less sophisticated technology are installed in less windy sites and are often subjected to more turbulent winds their performance is often much less than that of a utility-scale wind plant Based on a study of installed wind energy systems in Massachusetts a capacity factor of 10 would be considered rather high for most small wind installations2

Availability

Availability refers to a measurement of a turbinersquos reliability It is defined as the percentage of time that a turbine is able to generate electricity that is the time that the turbine is not down due to maintenance or repairs Modern utility-scale wind turbines strive for an availability of more than 98 Availability data for small-scale wind turbines is not currently available The availability of a small wind turbine would be highly dependent upon the reliability of the system the quality of the installation the wind resource and the level of system maintenance

2 Progress Report on Small Wind Energy Development Projects Receiving Funds from the Massachusetts Technology Collaborative (MTC) The Cadmus Group Inc (2008) 23 | P a g e

5 SITING ANALYSIS While the wind resource may vary throughout the proposed installation

site the point with the highest wind speed may not offer the safest or most economical installation option The positioning of a small wind turbine may be restricted due to many factors including site access performance social and legal considerations It is important to take these other variables into account when determining the appropriate positioning of a turbine

This chapter addresses small wind siting considerations that will help determine suitable installation sites Proper turbine siting is essential for optimum energy production and a reasonable economic payback

51 Site Access

The access of a potential installation site can restrict the ability to build upon the land Access to sites can be obstructed by many different variables including a lack of roadways extreme terrain or general remoteness These factors may not completely restrict access to the site but the cost of installation will increase dramatically with increased construction difficulty Furthermore the constructability of the land may be restricted due to environmental considerations ground composition or local regulations

52 Performance

Obstructions

The wind resource must be quantified to begin the siting of a small wind system Since the wind will fluctuate throughout the property and will vary with changes in the local terrain the ideal turbine location will be positioned where the wind speed is the highest and least obstructed The locations with the best available wind speed can be located with a wind map However small scale natural changes in the propertyrsquos topography and local obstructions may not be accounted for in published wind resource estimates Therefore a site inspection and analysis is needed to adjust the wind resource estimates to a more likely range

Careful consideration of the terrain is important when siting a wind turbine a turbine positioned on the top or the windward side of a hill has better exposure to high velocity wind than if it is installed in a gully or on the leeward side of a hill The prevailing wind direction is important to consider when positioning the turbine in close proximity to tall obstructions such as buildings

This chapter focuses on ground mounted installations only and does not consider building- mounted systems

The performance of wind turbines mounted on buildings is not well studied or documented and the wind around buildings can be very complex The building itself can significantly disturb the airflow around the turbine thereby adversely impacting a turbinersquos energy production and increasing wear and tear on the turbine In addition effects of the turbine on the building structure are not well understood

24 | P a g e

trees and geological formations As wind flows around an obstacle a wake forms immediately downstream This region of turbulent airflow has a much lower velocity than the undisturbed wind above Given that the available power in the wind is proportional to the cube of the windrsquos velocity this reduction in wind speed significantly reduces the turbinersquos ability to generate electricity

Turbulent winds not only adversely impact energy production but also increase the fatigue loads that the turbine will experience effectively shortening its operational life Therefore the recommended turbine siting is upwind of all major obstacles to ensure they are exposed to the least turbulent highest velocity winds available

Due to a small property size or an abundance of local obstacles it may be difficult to locate the turbine away from the detrimental effect of obstacles In these situations the height of the turbine becomes increasingly important since the effect of nearby obstacles can be decreased by increasing the height of the turbine Raising the height of the system can move the turbine out of the turbulent airflow caused by an obstacle and will increase turbine performance

The region of turbulent flow is approximately twice the obstacle height (H) and persists horizontally for roughly twenty obstacle heights (20H) as shown in Figure 10

Figure 10 Approximate region of turbulent airflow

t of E

25 | P a g e

In addition to moving the turbine to higher quality wind the turbine will experience increased wind speeds with increased heights which will lead to much greater energy generation While increased height can increase turbine performance other considerations can ultimately restrict the height of the system including the following

bull Additional space needed for raisinglowering the tower for maintenance

bull Increased space needed for guy wires

bull Increased construction cost

bull Increased setbacks from nearby structures

Collection System

Increased distance between the turbine and the electrical connection point will influence the overall cost and efficiency of the system A larger distance will result in increased wire lengths and will result in a higher cost that may not be recouped by the possible increase in available wind energy Longer wire runs will result in higher electrical losses in the collection system and will reduce the electricity supplied to the grid

If the turbine was certified by the Small Wind Certification Council (SWCC) the power curve includes the losses due to the collection system for a wire run length of at least eight rotor diameters from the base of the tower There is no standard guideline since the wire size can be increased to mitigate long wire run losses Still this should be a consideration during the siting and design process

53 Safety

Since small wind systems can have relatively high tower heights and are located in windy conditions the safety of the system is a major component of the siting process Safety issues include but are not limited to possible tower failure and collapse ice shedding and electrical issues

Wind turbines are typically setback from human occupied buildings to protect people if the tower were to fail Setbacks are also used for property lines power lines and roads A common distance for the turbine to be located away from property lines and power lines is at least the height of the turbine plus the length of the blades

Ice shedding results from accumulated ice on the turbine components shedding when temperatures increase and the ice melts While this condition can be hazardous it is not significantly different from ice shedding from other

In order to qualify under NYSERDArsquos incentive program (wwwPowerNaturallyorg) the turbine must have adequate setshybacks from houses and other buildings

26 | P a g e

structures such as power lines and transmission towers Ice could theoretically be thrown from the blades as they rotate but in practice ice typically sheds from the structure and falls near the base of the turbine In the rare case that ice is actually thrown from a turbine setbacks of at least the structure height will provide sufficient distance to protect against shedding ice Customers can apply in writing for an exemption from the NYSERDA incentive setback requirements

Wind turbines and inverters are professionally designed to be compliant with interconnection standards and safety requirements and rarely present major issues related to their interconnection to the grid However the turbine will be producing continuous power and the system must be treated with common safety practices Furthermore the installer of the system needs sufficient experience to safely design and install the system reducing the risk of electrical shock or failure For more information on interconnection standards and practices please consult the National Electric Code (NEC)

54 Social

Aesthetics

Since wind turbines are located at the top of tall towers and are sited to be in open unobstructed areas they may be viewed from distances beyond the property boundaries The visual impact of the turbine is affected by the turbine model tower height and local topography and obstructions The turbine owner may enjoy the sight of the turbine but neighbors and others in the community may have issues with being able to see the structure and may protest the turbinersquos installation It is recommended that you discuss your plans to install a wind turbine with neighbors early on Communication is important to help gauge the response of neighbors and communities and get their feedback on any major issues While the aesthetics of a turbine may not seem to be a major issue they can prevent a small wind project from proceeding

Furthermore limitations on visual impact within the local community may be restricted through community or historical site regulation For larger installations or instances with above average aesthetic concern a visual impact analysis may be warranted to determine the visual implications of installing a wind turbine Since the aesthetics of a small wind system are highly subjective and there are few laws or regulations specifically related to this issue there are no concrete guidelines for the siting of a small wind system The installer and property owner must be aware of the impact that the installation will have on the aesthetics of the property

27 | P a g e

Figure 11 Turbine sound pressure levels

Acoustics

Small wind turbines produce audible noise when operating which can usually be heard by nearby observers The sound generated by the system is created by both the mechanical components of the turbine and the aerodynamics of the rotating blades The intensity of the sound is affected by many variables including nearby surroundings turbine model hub height and wind resource Furthermore the noise increases with increasing wind speeds and decreases at a rate proportional to the square of the distance from the turbine

An additional consideration regarding on-site sound observations includes the increase in background noise that is observed with increasing wind speed which will partly mask the increased aerodynamic noise of the turbine

Since small wind turbines may be located in close proximity to people and residences accurate acoustic data and a realistic expectation of the systemrsquos noise are important The typical sound pressure levels for a small wind

system at a distance of 100ft are shown in Figure 11 making a small turbine comparable to the noise level in a home or office environment Therefore the turbine acoustics are usually at a reasonable intensity and can be avoided with proper siting setbacks

28 | P a g e

uporGlat

cerouS

For additional information on zoning and permitting please refer to the Appendix and the AWEA Small Wind Permitting Handbook at httpwwwaweaorgsmallwinddocumentspermittingpdf

Shadow Flicker

Shadow flicker is caused by the rotating blades of the turbine and causes a repeating pattern of shadows on nearby land and structures While this issue is typically associated with large utility scale wind turbines there is still an observed shadow flicker effect caused by small wind systems However the decreased rotor diameter and height of small wind systems drastically reduce the scale and negative implications of this phenomenon The property owner or neighboring structures will experience shadow flicker when the turbine blades are directly in between the sun and observerrsquos line of sight however due to setbacks from property lines and structures the issue of shadow flicker is almost entirely eliminated Furthermore since the sunrsquos position in the sky is constantly changing an observer will only experience shadow flicker at certain times throughout the day or season if at all

55 Zoning and Permitting

As the interest in wind energy increases more turbines are being installed in less remote locations where zoning and permitting policies need to be considered Zoning regulations are complicated since they not only vary from state to state but from one jurisdiction to the next Due to the inconsistency of zoning policy as well as the uncertainty surrounding local acceptance of wind energy projects it is generally advisable to secure the required permits before purchasing the equipment Additional material on the different types of zoning and permitting are included in the Appendix

29 | P a g e

ewur TS

cerouS

6 ENERGY PREDICTION An accurate estimate of the turbinersquos energy generating potential is

essential for customer satisfaction and an honest depiction of performance and economic payback The production capacity of the system depends on a variety of factors and can be estimated using the average annual wind speed wind speed frequency distribution turbine-specific power curve adjustment for air density and environmental and system losses Wind resource and energy estimates can be obtained from a variety of sources including on-site measurement publicly available wind maps turbine manufacturers installers and online tools and calculators To make the process straightforward and to provide interested parties with accurate wind resource and energy production data NYSERDA sponsors the Small windExplorer

61 Small windExplorer

The Small windExplorer provides detailed wind resource and energy production estimation tools to help facilitate the development of wind energy projects located throughout New York State The program offers these tools without the costly expenditure of measuring on-site data making the process g g p quick and economically feasible for small wind turbine installations

The program has a simple Web-based interface and allows the user to navigate to the specific turbine location to view and print wind resource and energy production reports This detailed data helps potential turbine owners and installers accurately estimate the annual energy output from a specific turbine at a given hub height and project location The wind resource information is based on the latest generations of validated wind maps developed by AWS Truewind

To better meet the needs of the different users of the program the program incorporates two separate printable reports that are

30 | P a g e

tailored to the different needs of the users After the user has selected the proposed turbine location it will be presented with two report options a basic and advanced wind resource report

The basic wind resource report is intended for end-users that are interested in installing a small wind system This report gives the information needed to determine the suitability of a small wind system on a property and will give the initial information needed for further consultation with an eligible installer The report will present the basic information regarding the available wind resource expected net energy output for various turbine rotor diameters and a qualitative review of their site specific wind energy potential Specifically the wind resource will be described by a wind map for the site a table displaying the annual average wind speed at three heights (80 ft 100 ft 120 ft) and an eight direction graphical wind rose

The advanced wind resource report is intended for eligible installers and provides the tools necessary to perform a more detailed feasibility study for a small wind project The advanced wind resource report incorporates much of the same information as the basic wind resource report including a wind map annual average wind speeds at three different heights and an eight direction wind rose Additionally the advanced report allows the user to enter information on each directional sector to help describe upwind obstacles and calculate the losses due to turbulence

31 | P a g e

62 Methodology

The steps involved in the Small windExplorer are shown in Figure 12 below Each step represents an important part of the energy estimation process and is detailed further in the following sections To perform an accurate energy estimate for a small wind turbine installation the entire process must be followed The Small windExplorer performs all the required steps and requires only minimal input from the user

Also included in the flowchart are example wind resource and energy production requirements for a NYSERDA sponsored incentive (wwwPowerNaturallyorg) For instance the average annual wind speed at hub height may be required to be greater than 10 mph and the annual energy consumption may not be allowed to exceed 110 of the propertyrsquos consumption For the most current NYSERDA incentive requirements please visit the NYSERDA Web site

Detailed instructions for using the Small windExplorer can be found in the Appendix

Figure 12 Methodology of the Small windExplorer

32 | P a g e

Wind Shear Adjustment

To begin the energy prediction process the average annual hub height wind speed must be known for the turbine installation Since the actual height of the turbine may differ from published wind resource estimates and maps the average annual wind speed may need to be adjusted to account for wind shear as discussed in Chapter 3 Therefore the Small windExplorer models the vertical wind shear profile using the Power Law The following example is provided to show the calculation performed in the program the user only needs to enter the tower height

33 | P a g e

The Power Law is described using the following equation

Where p = air density A = swept area of blades V = wind speed The wind shear exponent U is calculated using the following expression

Combining the above two expressions results in the following expression for V3 (extrapolated hub height wind speed at h3) as a function of known parameters

The wind speed at 110 ft can be estimated given the annual average wind speed at 120 ft and 100 ft where U(120 ft) = 122 mph and U(100 ft) = 117 mph The wind shear exponent is calculated using the two given heights and wind speeds

The wind speed at 110ft can then be calculated using the wind shear exponent and the wind speed at 100ft

Table 1 Wind speed frequency distribution

As discussed in Chapter 3 the frequency distribution of the wind is needed to accurately estimate the available power and is approximated using the Weibull distribution The average hub height wind speed 0 the Weibull shape factor k and the Weibull scale factor A are used to calculate the frequency distribution these parameters are given as output in the Small windExplorer The wind speeds are separated into regular increments or bins and the probability of a wind speed falling into a given bin is calculated using the Weibull expression

While the bins can be sized to any wind speed range the bins in the Small windExplorer are sized to 1 ms increments This bin width gives the needed accuracy for the calculations Table 1 shows an example wind frequency distribution table with 1 ms increment bins and the associated probability If performing these functions outside of the Small windExplorer a spreadsheet program will substantially decrease calculation time and the likelihood of error Table 1 Wind speed frequency distribution

d into 1 s binssseeparateparated into 1 mms bins

The Weibull distribution is modeled using the following equation within the Small windExplorer

Power Curve

Once the wind speed frequency distribution is binned the Small windExplorer uses the turbinersquos power curve to determine the gross energy production of the system As discussed in Section 43 the power curve displays the turbinersquos power output for varying wind speeds using the same bin concept as above The basic report uses a generic power curve weighted by swept area and the advanced report uses the manufacturer supplied power curve for the user selected turbine

34 | P a g e

The Small windExplorer assumes that the turbine power curve was measured using the AWEA Small Wind Turbine Performance and Safety Standard and certified by the Small Wind Certification Council (SWCC) As such the power curve will be sea level normalized and will be measured at the connection to the load therefore the losses associated with the turbine inverter and wiring will be included in the performance testing It is the responsibility of the installer to adjust the output estimates if the turbine has not been certified by the SWCC More information on the SWCC and the AWEA Small Wind Standards can be found at wwwsmallwindcertificationorg

The power level for each of the binned wind speeds is imported into the frequency distribution table Multiplying the power output at each wind speed by the probability of that wind speed gives the average power available in each bin Adding the individual powers for all wind speed bins gives the total average power available from the system Finally to calculate the annual gross energy available from the system the total average power is multiplied by the number of hours in the year as shown in the following equation

As shown below the gross power is equal to the wind probability multiplied by the applicable bin of the power curve The sea level gross energy is then calculated by multiplying the gross power by the number of hours in thee year

35 | P a g e

Air Density Adjustment

The above energy estimate assumes that there are no additional loss factors in the system and that the turbine will perform exactly as stated on the power curve However the production of the system will depend on multiple variables and the energy estimate needs to be adjusted accordingly

The power curves are given for standard sea level air density so a density adjustment must be applied to give an accurate description of the available power at the turbine location As discussed in Chapter 3 air density varies with changes in temperature and pressure and the amount of power in the wind is directly proportional to the density The program estimates the temperature and elevation of each site and calculates the site specific air density which is subsequently used to adjust the gross energy

The site specific air density is calculated using the following equation

Where p = Air density (kgm3) P0 = Standard sea-level atmospheric pressure in Pascals (101325 Pa) R = Specific gas constant for dry air (287 JKgmiddotK) T = Air temperature (K) T(K)=T(degC) + 27315 g = Acceleration due to gravity (98 msec2) z = Elevation of temperature sensor (m)

As an example the air density adjustment at a site with an elevation of 357 m and mean annual temperature of 10degC is approximated below

As shown above the temperature and elevation of the site decreased the air density by 27 resulting in an equivalent increase in the adjusted annual gross energy

36 | P a g e

Losses

There are many losses in small wind systems that need to be taken into account in the energy estimate The basic report assumes generic losses and the advanced report allows users to enter their own estimated losses

Turbulence Losses

As discussed in Section 51 local obstructions and terrain can impact the available wind resource by decreasing the observed wind speed and increasing turbulence Since these environmental factors may not be accounted for in available wind resource maps they must be manually entered The losses due to turbulence are approximately equal to the sitersquos turbulence intensity The basic report assumes a generic loss of 20 for turbulence intensity and the advanced report includes a data entry page to help estimate the losses caused by the local terrain

The Small windExplorer estimates turbulence losses by calculating the estimated ambient turbulence intensity using the surface roughness and turbine hub height

Turbulence losses are weighted by the percentage of energy that is expected from each direction and then combined to compute a total turbulence loss for the site

Other Losses

In addition to the losses associated with the surrounding environment the turbinersquos performance will be affected by losses due to the collection system inverter efficiency and system availability As noted earlier the power curve will include inverter and collection system losses Availability can be associated with the electrical grid downtime and any downtime due to maintenance or system failures These losses depend on the model of turbine and inverter and the level of maintenance the system will experience To account for the availability of the system the Basic Report includes an Availability Loss factor of 20 and the Advanced Report allows the user to enter the expected Availability Loss

If the inverter or wire specifications are different than those in the power curve performance test or if the system is expected to have additional environmentalsystem losses the losses can be adjusted accordingly in the

37 | P a g e

Advanced Report using the Additional Known Losses field on the data entry page

Uncertainty

There are many uncertainties in the energy prediction process which lead to uncertainties in the annual energy estimate The main sources of uncertainty include the estimation of the wind speed and loss factors The basic report does not take these factors into account and instead gives a basic approximation for net energy The advanced report uses approximated uncertainties for the different sources to create a range in energy production

The wind speed estimates used in the Small windExplorer have an uncertainty of approximately 70 which accounts for the inter-annual variability of the wind speed Therefore the upper and lower bounds of the gross energy estimate are calculated by increasing and decreasing the annual average wind speed by 70 respectively Adjusting the wind speed changes the frequency distribution which has a direct effect on the total amount of energy available in the wind therefore the program runs three different scenarios for the varying wind speeds to calculate the range in energy production

The uncertainty in estimating the losses is much harder to predict Therefore this uncertainty is estimated at 20 of the total loss which is directly applied to the above energy range

63 Economic Analysis

After the annual energy production of the system has been estimated it is important to perform an economic analysis to determine if the wind energy system is worth installing

An economic analysis should include the total system and itemized costs applicable incentives payment schedule a quote for routine maintenance for a minimum of the first two years and economic analysis The routine maintenance quote must include information on scope timing and cost of routine maintenance items

The analysis shall use the annual energy estimate range along with the end-userrsquos electricity cost to produce a realistic economic payback The economic payback will help the end-user understand the economics of the wind system and the amount of time needed to payback to initial investment

For systems that meet certain requirements NYSERDA provides generous monetary incentives For more information on the incentive levels requirements applications and timing refer to the NYSERDA Web site (httpwwwpowernaturallyorg)

38 | P a g e

7 NYSERDA INCENTIVE NYSERDA has sponsored incentives to encourage the development

of a network of Eligible Installers who will install end-use wind energy systems for residential commercial institutional or government use The incentives range in size and will be paid to Eligible Installers who install approved new grid-connected wind generation systems using qualified equipment Eligibility requirements are described on NYSERDArsquos Web site (wwwPowerNaturallyorg)

Incentives are intended to benefit both the installer for business development and the wind generation system owner where generated power offsets the customerrsquos utility power purchases The Eligible Installer must pass incentives directly to their customers Incentive levels depend on wind generator size tower height and customer type and are posted o n NYSERDArsquos Web site (wwwPowerNaturallyorg)

Installer eligibility is determined and maintained for specific equipment based on training and professional experience Once deemed eligible installers then apply for and reserve on a first-come first-served basis NYSERDA incentive awards for approved new grid-connected end-use wind generation systems

Interested potential owners wishing to participate in this program are encouraged to contact several Eligible Installers for recommendations and quotes for a wind system A list of Eligible Installers is posted on wwwPowerNaturallyorg

bull Incentives are paid to eligible installers that have been approved to participate in the program

bull The entire incentive must be passed on to the owner of the wind system by the eligible installer

bull The prospective turbine owner should work with the installer to obtain all necessary pre-construction permits approvals certificates etc from all jurisdictions having authority prior to ordering equipment since NYSERDA will not process any payments without proof that all permits have been obtained

bull Incentives will not be paid for wind systems installed by contractors or individuals that are not on NYSERDAs list of eligible installers which can be found at wwwPowerNaturallyorg

39 | P a g e

8 OPERATIONS AND MAINTENANCE

81 Installation

Once the wind system has been determined to be economically feasible and after all permits and incentives have been approved the wind system must be installed by an Eligible Installer Depending on the type of turbine and foundation the installation time can vary The foundation will take two to three weeks to cure and the actual tower installation will take approximately 2-3 days

A proper installation alone does not result in efficient operation and energy production it is instead an important first step and should be followed by regular maintenance and inspections

82 Maintenance

The amount of maintenance that a small wind system needs varies depending on the turbine manufacturer installation method and wind resource Typical wind generator system maintenance includes regular oiling and greasing of turbine components and routine safety inspections Bolts and electrical connections must be checked annually along with the tower plumbing guy wire tension and all areas for corrosion Blades must be checked for damage or decay and a bladersquos leading tape should be replaced to protect the turbine and ensure efficient operation

Since most maintenance procedures require a technical background and knowledge of the turbine installation all maintenance must be performed by the installer or other qualified individual The end-user should pay close attention to the systemrsquos operation and production and contact the installer with any major changes in system production or safety concerns The end-user should record the turbine energy production every month to track performance and should regularly visually inspect the installation Keeping a close eye on the system will ensure greater availability and a longer lifetime for the system

To qualify for a NYSERDA incentive the system must be installed by an Eligible Installer Eligibility will be based on factors such as acceptance of all program terms and conditions training extent and type of installation experience customer references and meeting the insurance requirements of this program

Installers must provide a five-year system warranty The warranty must cover all components of the generating system against breakdown or degradation in electrical output of more than ten percent from their original rated electrical output The warranty must cover the full costs including labor of repair or replacement of defective components or systems

Installers must also provide instructions for maintenance and a quote for annual maintenance costs

40 | P a g e

83 Follow-Up Inspections

Follow-up inspections performed by the installer are important to ensure proper turbine operation and safety standards Inspection and maintenance schedules will vary between different types of systems and are usually detailed in the turbine and tower manufacturer user manuals For guyed towers the installer should inspect guy wire tension approximately 30 and 180 days after installation3 Following these initial inspections the system should be checked on an annual basis or after severe weather These will typically be at an extra cost and will be included in the installerrsquos quote for regular system maintenance Annual inspections will include but are not limited to the following

bull Inspect each anchor point

bull Check guy wire tension

bull Check tower plumbing

bull Turbine control system if any

bull Blade condition (cracks leading edge tip)

bull Bolts fasteners bearings wires

bull Electrical connections wire run inverter

Once again the specific inspection and maintenance needs should be addressed in the individual turbine and tower user manual and will vary between technologies and manufacturers

If a NYSERDA incentive was awarded NYSERDA reserves the right to make a reasonable number of visits to the customer site during and after installation of the wind generation system The purpose of the site visit(s) is to provide NYSERDA with an opportunity to evaluate the installed wind generation system and make sure it was installed according to the information presented in the application

3 BWC EXCEL Installation Manual Guyed Lattice Tower 41 | P a g e

9 CASE STUDIES

91 Alfred University Alfred State College Farm

42 | P a g e

43 | P a g e

92 Apple Pond Farming Center

44 | P a g e

45 | P a g e

93 Olde Chautauqua Farm ndash Portland NY

46 | P a g e

47 | P a g e

94 Weimann Farm ndash Locke NY

48 | P a g e

49 | P a g e

10 APPENDIX

A1 Zoning and Permitting

As the interest in wind energy increases more turbines are being installed in less remote locations where zoning and permitting policies need to be considered In general zoning policies designate acceptable uses of land within a given area permits are required for uses that are not generally accepted or require additional regulation Zoning regulations are complicated since they not only vary from state to state but from one jurisdiction to the next Due to the inconsistency of zoning policy as well as the uncertainty surrounding local acceptance of wind energy projects it is generally advisable to secure the required permits before purchasing the equipment

Where to Start

It is important to research the local zoning restrictions that effect non-dwelling structures There are three levels of local government that can influence zoning regulation county township and municipality Wind turbines are not always specifically addressed in the zoning codes as an allowed or permitted use Non-listed uses are generally considered prohibited and are only allowed through the use of a conditional use permit or a variance from the existing code These permitting policies are explained in greater detail below along with other review options that may be applicable depending upon the zoning policy in the region

Permitted Use

Permitted uses are those that are allowed under all circumstances as long as they meet applicable design standards This approach is commonly applied to structures such as flagpoles grain silos and church steeples For small-scale wind turbines this type of permitting policy is more likely to be implemented in rural areas where the impact of a small wind turbine installation on neighboring properties is expected to be minimal

Special Use

A special or conditional use permit allows the installation of a small wind turbine if it meets the criteria outlined in the conditions of the permit This type of regulation is employed when the use in this case the installation of a small wind turbine is regarded as generally appropriate for the zone but not in every circumstance Consequently the use is subject to conditions to make certain that its impact on the surroundings is minimal A public hearing andor more detailed documentation of the project may be required in order to obtain a special use permit

Variance

A variance is a modification or waiver to a particular zoning regulation For small wind turbines variances frequently deal with exceptions to required setback distances or structure height restrictions The issuance of use

50 | P a g e

variances serves as a method to handle unanticipated and appropriate exceptions to zoning ordinances In obtaining a use variance the burden of proof as to the appropriateness of the use rests with the applicant

Accessory Use

An accessory use is one that is secondary to the principal use of the property For small wind turbines this accessory use is typically applied to agricultural industrial or commercial settings where the energy produced by the turbine is required to fulfill the propertyrsquos principal purpose

Overlay Zone

An overlay zone replaces the zoning regulations within a particular region To shorten the permitting process jurisdictions may create a specified zone that has been determined to be appropriate for small wind turbines or wind energy development in general

Site Plan Review

A site plan review is a process used to verify the installation is designed and constructed in an appropriate manner prior to the issuance of a building permit The site plan review involves an evaluation of the proposed project by the local Planning Board and may require a physical inspection of the project site and its surroundings prior to installation This policy is typically used as a supplementary tool in the evaluation of proposed wind projects and is generally associated with an application for a special use permit

Permits and Codes

Building Permit

As is the case with zoning regulations the requirements for permits and codes vary with each locality Typically the construction of a small wind turbine will require a building permit As part of the building permit application process a plot plan may be requested which outlines the details of the proposed wind project A plot plan usually indicates the following

bull Property lines and physical dimensions of the property bull The location dimensions and type of existing major structures on the property including proposed location of

the wind turbine bull The location of public roads as well as any overhead utility lines bull The distances from the proposed turbine location to surrounding structures bull The specifications of the wind turbine including manufacturer and model rotor diameter tower height and

tower type (freestanding or guyed) bull Blueprints or drawings of the tower and foundation are helpful

51 | P a g e

Note that these plot plan requirements will vary it is best to consult the local ordinance to identify the requirements specific to your project In some instances zoning regulations may go to the extent of requiring an engineering analysis of the tower and foundation

Electrical Permit

Some jurisdictions may require an electrical permit for the installation of a small wind turbine If required an electrical inspector will inspect the system to ensure that it complies with the standards outlined in the National Electric Code (NEC) The system may not be allowed to generate until it has been inspected and approved as compliant with the NEC

If the wind turbine is interconnected with the electrical grid the utility may require that an application be submitted describing the system and equipment As part of the review process the utility may want to inspect the system to verify that it complies with the NEC The utility will often require that a one-line diagram of the system which describes all of the electrical components be submitted Once the utility is satisfied that the system meets the necessary prerequisites it will enter into an interconnection agreement with the turbine owner

The Federal Aviation Administration (FAA) regulations need to be considered only if the total structure height is greater than 200 feet or located within 3 frac34 miles of a commercial runway The vast majority of small-scale wind turbines are below 200 feet in height If the proposed turbine location is within the 3 frac34 mile radius form 7460 must be submitted to the FAA so that it can determine if any restrictions need to be observed regarding the towerrsquos height or location or if obstruction lights are required

State Environmental Quality Review Act

The State Environmental Quality Review Act (SEQRA) process was established to consider the potential impact on the environment when planning projects that are undertaken funded or approved by a State or local agency Any NYSERDA funded project will require a SEQRA process to review for significant adverse environmental impacts

There are three possible actions that can be pursued in a SEQRA referred to as Type I Type II and Unlisted Actions A Type II action is considered not to have any significant adverse impact on the environment NYSERDA explicitly states that the installation of a wind turbine cannot be considered a Type II action or an Unlisted Action Therefore wind projects must be considered a Type I action by default meaning that it is assumed to have a significant adverse impact to the environment

Installerrsquos Responsibilities

The requirements to fulfill the SEQRA process can vary depending upon the zoning regulation of the local government as well as aspect of the project itself The following guideline can be consulted to help determine the responsibility of the installer

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Does the local government have zoning

YES ndash If the local government has zoning regulations regarding small wind turbines then the following requirements need to be fulfilled

bull Appropriate Environmental Assessment Form (Full or Short) bull Visual Environmental Assessment Form Addendum bull Evidence that the local government has discretionary permitting authority (copy of zoning) bull Relevant SEQRA document

o Appropriate Environmental Assessment Form o Declaration and notice of coordinated review from lead agency o Resolution by the local government (if available) o Letters of project acceptance from neighbors within 300 feet of the proposed project installation

NO ndash If the local government does not have zoning regulations then the total height (tower + rotor) of the structure must be considered

Is the total height 100 feet or greater

YES ndash If there is no local zoning and the total structure height is 100 feet or greater it is recommended that NYSERDA be contacted to determine how to proceed NYSERDA will typically require the following

bull Full Environmental Assessment Form bull Visual Environmental Assessment Form Addendum bull Project Description Memo ndash details project and answers questions contained in Parts A B and C of the

Full EAF or Part II of the Short EAF bull Letter from local government confirming that no zoning policies are applicable bull Letters of project acceptance from neighbors within 300 feet of the proposed project installation site

NO ndash If there is no local zoning and the total structure height is less than 100 feet

bull Appropriate Environmental Assessment Form (typically the Full EAF) bull Visual Environmental Assessment Form Addendum bull Project Description Memo ndash details project and answers questions contained in Parts A B and C of the

Full EAF or Part II of the Short EAF bull Letter from local government confirming that no zoning policies are applicable bull Contact information for the local government(s) and counsel

Letters of project acceptance from neighbors within 300 feet of the proposed project installation site

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Environmental Assessment Forms (EAF)

There are three types of Environmental Assessment Forms (EAF) that the SEQRA process may require to evaluate the potential environmental impact of a small wind project

Full Environmental Assessment Form (21 pages)

The Full EAF is required for any Type I action The form is comprised of three parts the first part requests information concerning the project including a description of the proposed site and project as well as applicable zoning regulations The second part attempts to identify the potential adverse impacts that the proposed project may have on the environment The third part gauges the significance of the impact

bull The front page is to be completed by the lead agency bull Part I (Sections A B amp C) is to be completed by the OwnerInstaller bull Parts II amp III are to be completed by the OwnerInstaller on behalf of NYSERDA

Short Environmental Assessment Form (2 pages)

The Short EAF is an abbreviated version of the Full EAF and is only intended for Unlisted actions

bull Part I is to be completed by the OwnerInstaller bull Parts II amp III are to be completed by the lead agency

Visual Environmental Assessment Form Addendum (2 pages)

The Visual EAF is used to evaluate the potential visual impact that the proposed project could have The Visual EAF is generally used in conjunction with a Full EAF but may also be used with the Short EAF This evaluation process focuses on the following describing the existing visual environment assessing the visual impact of the project determining who will see the project and in what context and identifying the visual compatibility of the project with the surroundings

bull Both pages should be completed by the OwnerInstaller

Lead Agency

Any involved agency (government agency that has the authority to fund approve or permit or directly undertake the project) can become the lead agency For the review of small wind projects the Town is generally the lead agency

Evaluation of EAF

After the EAFs have been submitted the lead agency will assess the significance of the proposed projectrsquos environmental impact If the project is determined not to have significant adverse environmental impacts it will receive a negative declaration If the project could have a potentially significant effect but measures can be taken mitigate the projectrsquos environmental impact a conditional negative declaration will be issued Lastly if the proposed project is determined to have a significant adverse impact to the environment the project will not receive a positive declaration

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If a project receives a positive declaration an Environmental Impact Statement (EIS) will be required to evaluate how to avoid or reduce the projectrsquos adverse environmental impact

Additional Resources

SEQRA Information for small wind installers httpwwwpowernaturallyorgProgramsWindInstallersInfoaspi=8 Department of Environmental Conservation wwwdecnygov Flow chart of the SEQRA process httpwwwdecnygovpublic32521html

55 | P a g e

A3 Small windExplorer Instructions

How to Navigate the Application

1 Zoom to a point of interest a Use your mouse to click anywhere on the map frame or b Explore the wind map by entering your location in the box provided Accepted inputs include latitude

and longitude coordinates in decimal degrees or degrees minutes seconds and street address

When you select a location the application will automatically zoom to that spot A push pin will appear and the coordinates will be displayed below

2 Navigate the New York State wind map using standard Google Maps tools

a Zoom in or out by dragging the line up or down the scale bar You may also click on either the plus or minus signs to zoom in or out respectively

b Pan by clicking the up down left right buttons or by holding down the cursor and dragging the mouse c Zoom to the full extent of valid data by clicking on the center button d Zoom in to an area using the custom zoom tool

Please note that the wind map will disappear when you zoom in beyond a certain extent

56 | P a g e

3 Toggle the display using standard Google Map overlays

Click on Map Satellite Hybrid or Terrain buttons to change the underlying base map

4 Change the wind maprsquos height level

Select from one of three map heights above ground level 80 100 and 120 feet by using the drop-down menu This affects the both map display and the displayed wind speed underneath the Google Map frame

5 View your wind speed for the selected location

The mean annual wind speed (in miles per hour) will be displayed in the informational box provided underneath the Google Map frame This value is the mean annual wind speed at that location in miles per hour

6 Generate a Wind Resource Report

Click the Generate Report button and follow the on-screen instructions

How to Generate a Report

After clicking the Generate Report button the Data Entry Page will load For the Basic Report the user must enter his or her name and address to be included on the output report For the Advanced Report after logging in the user must enter the following information

bull Name ndash of property owner where the turbine is to be installed (required) bull Address - where the turbine is to be installed (required) bull Turbine Model (required) bull Hub Height (required) bull Terrain description for each directional sector (assumed if not entered) bull Availability Loss (assumed if not entered) bull Additional Known Losses (assumed if not entered)

Turbine Model

Select a small wind turbine model to use in the analysis Only NYSERDA qualified wind generators are included

Hub Height

Enter the proposed tower height in feet

Terrain Description

Select a terrain description that best matches each given direction as seen from the tower This description will help estimate the effects of upwind terrain and obstacles on energy production

Availability Loss

Enter the expected loss due to turbine availability

Additional Known Losses

Enter additional environmental or system losses As designed the program assumes that all turbine power curves have been measured using the AWEA Small Wind Turbine Performance and Safety Standard if the manufacturer supplied power curve was not created using this standard an adjustment factor can be entered

Once all fields are entered click the Submit button to generate the applicable report

57 | P a g e

How to Interpret the Basic Report

1 Determine your sitersquos Wind Energy Potential

This ranking will give you a qualitative assessment of the sitersquos available wind resource

2 Determine your sitersquos estimated wind resource and annual net energy

The table presents data at three different heights (80 100 120 ft) If any of the heights have an estimated wind speed of less than 10 mph a warning will appear for the user The energy estimates provide information for various rotor diameters

3 View your sitersquos 200 m (656 ft) wind map and wind rose data

The sitersquos wind resource map shows the average annual wind speed at 100 ft above ground level The wind rose provides an estimate for the amount of energy located in each directional sector (N NE E SE S SW W NW)

4 Contact a NYSERDA eligible wind installer with this wind resource report for further consultation

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How to Interpret the Advanced Report

1 Determine the sitersquos characteristics and available wind resource

The sitersquos latitude longitude elevation average annual wind speed at hub height frequency distribution parameters and surface roughness are displayed

2 View the sitersquos 200 m wind map and wind rose data

The sitersquos wind resource map shows the average annual wind speed at 100ft above ground level The wind rose provides an estimate for the amount of energy located in each directional sector (N NE E SE S SW W NW)

3 Review the system losses and estimated annual energy production

Turbulence induced losses availability losses and additional known losses are summarized along with the estimated minimum and maximum total losses The net energy summary displays the estimated range in annual energy production based on the chosen wind turbine local wind resource selected loss factors and interannual variability in the wind

Review the satellite image with wind rose graphic to verify that the selected terrain roughness values match each direction

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For information on other NYSERDA reports contact

New York State Energy Research and Development Authority

17 Columbia Circle Albany New York 12203-6399

toll free 1 (866) NYSERDA local (518) 862-1090

fax (518) 862-1091

infonyserdaorg wwwnyserdaorg

FINAL REPORT 10-08

STATE OF NEW YORK DAVID A PATERSON GOVERNOR

NEW YORK STATE ENERGY RESEARCH AND DEVELOPMENT AUTHORITY VINCENT A DEIORIO ESQ CHAIRMAN FRANCIS J MURRAY JR PRESIDENT AND CHIEF EXECUTIVE OFFICER

DA Final R

eport 10-08

Structure Bookmarks